Waking up in the morning with drool in your mouth and a yellowish odor may be caused by personal bad habits, or it may be related to oral diseases, gastrointestinal diseases, gallbladder diseases and other pathological factors. 1. Personal bad habits: such as eating food before going to bed and not brushing your teeth in time, resulting in food debris in the oral cavity reproduction of bacteria, resulting in waking up with saliva in the mouth and the symptoms of yellowing and stinking. 2. Pathological factors. (1) oral diseases: such as dental caries, periodontitis, gingivitis, etc. can cause long-term accumulation of plaque, bacteria breeding in the mouth, morning saliva mixed with tartar, food debris and bacteria can appear stinky, yellowing symptoms. At the same time, it can also be accompanied by symptoms such as swollen and painful gums, bleeding and so on. (2) Gastrointestinal diseases: such as chronic gastritis combined with Helicobacter pylori infection, gastroesophageal reflux disease, etc., gastric acid reflux bacteria can also be followed into the oral cavity, resulting in waking up with saliva in the mouth and yellowish and smelly symptoms. (3) Gallbladder diseases: such as gallbladder stones, cholecystitis, etc. can cause bile reflux, may wake up in the morning with saliva in the mouth and yellow, foul-smelling, and may be accompanied by symptoms such as bitter mouth. After improving the bad oral habits, if the above symptoms still occur for a long time, it is recommended to consult a doctor in time to find out the cause of the yellowish and smelly saliva in the morning, and then treat it under the doctor’s guidance to avoid delaying the condition.